The present invention concerns wheelchairs used by handicapped persons and invalids and relates to self-propelled chairs and possibly folding chairs.
The object of the invention concerns more particularly wheelchairs of the type comprising an articulated structure including a back portion, a seat and a foot-rest associated with a motor element for assisting or ordering the lifting or lowering of the articulated structure with respect to a carrying frame.
These wheelchairs undoubtedly represent real progress as, apart from providing essential mobilisation, they enable the occupant to be rendered vertical which is also essential so as to avoid physical discomfort arising from remaining too long in a seated position.
The prior art offers a certain number of solutions for embodying wheelchairs comprising an articulated stand-up structure.
These various solutions have advantages and drawbacks, but generally speaking make it possible to correctly render an occupant standing up correctly.
However, it has been observed that these wheelchairs could not have been used by all handicapped persons or invalids. In fact, for certain handicapped or disabled persons, the occupant concerned does not have or no longer sufficient has muscular control to remain in a stable position against the stand-up support plane represented by the raised articulated structure of a wheelchair.
In these cases, remaining upright represents a real danger for the occupant who, without possessing physical control, risks falling by being moved sideways or by the bending of the legs or even by weakening of the torso.
Now the possibility of remaining upright is important for all handicapped persons or invalids and even more so for those not possessing physical control such as in the cases mentioned above.
In order to resolve this problem, it has been suggested, in particular in the patent FR 83 08 201, to adapt a body support device on these wheelchairs, said device including:
A first set of means comprising two partly bent rigid segments each mounted laterally on the corresponding upright of the back portion by an articulated system and able to be arranged:
Along a general vertical orientation in which they represent side rail armrests for an occupant,
Or along a general horizontal orientation in which they constitute a thoracic strap for the occupant,
And a second set of means including two cradles mounted by hinge pins on the front uprights of the foot-rest unit, said cradles being associated with relative immobilisation means in an alignment position in which they constitute open elastic stockings nesting via the front the legs of an occupant.
The means described above shall be considered as able to essentially respond to the problem of an occupant being moved to a standing position and supported in the phases for lifting up and lowering the articulated structure so that the body of said occupant is suitably supported safely.
The backward movement, now available concerning the use of these stand-up wheelchairs, has however revealed the need to improve some of the technical means implemented to provide body support and more particularly the technical means relating to the second set and intended to ensure locking on bending of the lower limbs of the occupant by the immobilisation of the legs immediately below the joint of the knees.
In fact, it has been observed that the relative immobilisation means in a position of the alignment and nesting of the open elastic stockings did not provide all the safety required and essential for reasons due to their design.
These immobilisation means are sometimes rudimentary and thus advantageous on account of their simplicity concerning their design and handling, but on the other hand are dangerous for the safety of a sick person, especially in a standing up position given the fact that there is a possibility or risk of said means being opened at the wrong time.
Other mobilisation means basically seek to eliminate this major drawback and are then designed so complex as to be expensive in terms of design and upkeep and in particular are difficult to be activated in a practical and ergonomic way by a handicapped person or invalid.
Furthermore, so as to offer full safety to an occupant when standing up, it has been observed that it is essential to take into account a risk of incorrect handling of the locking means and taking account of this to nevertheless introduce in some way to a second degree a passive element of safety to guarantee at least partial safety should the mobilisation means open at an inopportune moment.
Thus, the object of the invention is to satisfy this need for improving the immobilisation means of the open elastic stockings so that these means are effective, can be easily activated, are reliable and being of the kind to further offer an additional passive safety for supporting the elastic stockings in a nesting position, even if, although unlikely, these immobilisation means are manoeuvred at the wrong moment or rendered defective to the point of resulting of causing an unintentional opening.
So as to attain this objective, the locking system for a body support device for a stand-up wheelchair including a chassis supporting an articulated structure composed of a seat, a back portion and a foot-rest associated with two open elastic stockings constituted by two cradles borne by supports having an articulation function via tilting on the foot-rest and a linking function by means of a locking system intended to firstly immobilise between them said supports in a position in which the elastic stockings house the legs of a sick person, and secondly enable the supports to be opened, said supports being constituted by two frames forming two tilting arms and two frontal arms provided at the end of additional fundamental elements of the locking system,
is characterised in that:
the additional elements are constituted by half nuts shaped so that in their co-operation position to give rise to a mortise and tenon type assembly inside in an approximately horizontal plane,
One of the half nuts delimits inside the tenon an open housing with an axis perpendicular to the assembly plane and into which a guiding chute projects opening towards the front,
And the other half nut bears an elastic return thrustor traversing the mortise along a direction perpendicular to the assembly plane and forming a body able to be engaged in the housing and a neck for traversing the chute.